A triptycene-based 2D metal-organic framework with vertically extended structure as filler and guide layer for stable...

Quasi-solid-state lithium-metal batteries (QSSLMBs) based on gel polymer electrolytes (GPEs) have emerged as promising next-generation energy storage systems in view of their high security and energy density. However, challenges remain in improving the compatibility of the electrode-electrolyte interface and promoting Li⁺ conduction. Herein, we developed the composite polymer electrolytes (CPEs) by using a vertically-aligned two-dimensional conjugated metal-organic framework (Cu-HHTC) as the filler of GPEs. The optimized CPE (CPE-0.4) demonstrates higher Li⁺ transference number (0.81) and ionic conductivity (1.59 × 10^-3 S cm^-1). Remarkably, Li|Li symmetric cells exhibit long-term cycling stability exceeding 3200 h at 0.1 mA cm^-2. Meanwhile, the assembled full cell (LiFePO₄|CPE-0.4|Li) offers a reversible discharge capacity of 161.4 mAh g^-1 at 0.5C and maintains a high-capacity retention of 82.6 % after 1000 cycles at 1C. In addition, as a proof-of-concept, anode-free QSSLMBs (AF-QSSLMBs) with Cu-HHTC modified-Cu (LiFePO₄|CPE-0.4|Cu-HHTC@Cu) were constructed, which demonstrates impressive electrochemical performance. This study not only highlights the multifunctional role of 2D c-MOFs in developing QSSLMBs, but also provides a strategic pathway for designing practical AF-QSSLMBs.